Apparatus and method of treating bulk material



Sept. 30, 1941. r F. 5. SMITH 2,257,541

APPARATUS AND METHOD OF TREATING BULK MATERIAL Filed June 26, 1937 4Sheets-Sheet l INVENTOR flan/01in 1S. Smylth BY fil l M V 'J ATTORNEYSSept. 30, 1941. F. s. SMITH 1 7,

APPAR TUS AND METHOD OF TREATING- BULK MATERIAL Filed June 26, 1937 4She'ets-Sheet2 p 1941- F. S. $M|TH 2,257,541

APPARATUS AND METHOD OF TREATING BULK MATERIAL Filed June 26, 1957 4Sheets-Sheet s Fng dclin 15'. Smith fiat; I J

ATTORNEYS Se t. 30, 1941. F, s SMI 2,257,541

APPARATUS AND METHOD OF T IiEATING BULK MA TERIAL Filed June 26, 19 37A: Sheets-Sheet 4 INVENTOR Franklin bijsmith MY/ 4%. W 0 M ATTORN videfor the treatment, in

Patented Sept. 30, 1941 APPARATUS AND METHOD OF TREATING BULK MATERIALFranklin S. Smith, New Haven, Conn.

Application June 26, 1937, Serial No. 150,522

19 Claims.

This invention relates to the treatment of materials and more inparticular to the art of and apparatus for the electrical treatment ofmaterials for purposes such as the destructionof insect life, which termas herein used incl'ides the egg, larva, pupa, and adult states ofinsects.

Among the objects of this invention is the provision of practicalapparatus of simple and durable construction and eflicient anddependable action. Further objects are to provide apparatus of the abovenature for avoiding an explosive mixture of air and dust, for providingand regulating a desired electrical potential, for remov ing ozone andthe like from the finished product, and for the preventionof excessiveheat at certain points.

Other objects are to provide practical methods or arts for achieving theabove aims which may.

be readily carried on and shall be characterized by certainty of thedesired results.

Other objects will be in part obvious and in part pointed outhereinafter.

The invention accordingly consists in the features of construction,combinations of elements, arrangements of parts and in the several stepsand relation and order of each of the same to one or more of the others,all as will be illustratively described herein, and the scope of theapplication of which will be indicated in the following claims.

In the drawings;

Figure 1 is a view partly in elevation and partly broken away,disclosing the general assembly of the apparatus;

Figure 2 1s a vertical sectional view of the motor and certain of itsassociated parts;

Figure 3 is a horizontal sectional view on the line 3-3 of Figure 1;

Figure 4 is a vertical sectional view on the line 4-4 of Figure 3;

Figure 5 is a horizontal sectional view on the line '5-5 of Figure 1;

Figure 6 is a plan view of the assembled machine; and

Figure 7 is an enlarged view of means for ing band In in place.

Certain broad features of this invention contemplate the continuoustreatment of materials holdby high-potential electrical dischargesthrough I a gaseous dielectric and the provision of a method andapparatus for carrying on this treatment with safety in a thoroughlyefficient and practical manner. An object of this invention is to protheabove-mentioned manner, of materials such as cereals, seeds, grains,corn, beans, etc.

This treatment is especially effective in completely destroying theinsect life of all of the various insects of the type which infestproducts of relatively small particle sizes, such as coursely milledcereals, semolina, farina, grits, etc. However, in the treatment ofproducts, it has been found that the desirable characteristics, such asviability of seeds, color and baking properties of flour, etc., areunimpaired.

Treatment such as that contemplated in the present invention isparticularly important ir.

. milling or similar operations where insect life is iii continuallybeing introduced into the milling machinery by infested grain, Undersuch circumstances, certain eggs and small larvae are not destroyedduring the milling process, but often lodge within the equipment andform foci of infestation where they propagate and spread to the finishedmaterial. However, if the grain, or other material, entering the millingequipment is treated in accordance with the teachings of this invention,this insect life will be destroyed and infestation within the equipmentwill be sub-' stantially lessened if it eliminated.

In the present embodiment, means is provided is not completely to passthe grain or other material between two electrodes through an area whichis termed the treatment zone. A relatively high-frequency, highelectrical potential is maintained across the electrodes with the resultthat when the material passes through the zone, an electrical dischargeoccurs between the electrodes. It has been found that thisdischargeseeks out and destroys insect life of the nature referred toabove.

Very satisfactory results have been obtained with the use of a pair ofannular, horizontally positioned, electrodes, the upper electrode beingstationary, and the lower electrode being rotatable. During operation,the grain or other materialis passed upon the upper surface of therotatable electrode near its center and moves outwardly due tocentrifugal force so that it is thrown through the treatment zone.

Under certain conditions, dust accompanying or forming part of thematerial being treated, might be so distributed in the oxygen present toform an explosivemixture. However, when desirable, an additionalquantity of air, or other gaseous dielectric, such as' carbon dioxide,is mixed with the material being treated immediately priorto its passagethrough the treatment zone; thus, the dust concentration is brought Whenthe material being treated is surrounded by air, the corona-likedischarges produce ozone and certain oxides, such as oxides of nitrogen,all of which shall be referred to as airionization products. Y blowingair through the treatment zone with the grain and then providing meansfor removing air from the machine, the air-ionization products areeifectively removed from the treatment zone, and the machine, and, atthe same time, heat produced incident to the treatment process isremoved from the machine.

The general construction of the illustrative embodiment herein set forthis shown in Figures 1 and 6 where it will be seen that the apparatus ismounted upon a frame of rectangular tubing which includes three pairs ofvertical posts I (Figure 6), the tops of the posts of each pair beingconnected by a crossbar II. Mounted upon crossbars II is the upperhousing-ring 6 (Figure '1) of a casing-supporting frame. Thecasingsupporting frame provides mounting means 'for the entire'casingand also includes four downwardly-extendingarcu ate'brace plates 203,supporting a lower housing-ring 3 across which extend two horizontalrails 5. Attached to the under side of lower housing-ring 3 isa'funnellike hopper I which receives the treated grain and directs itinto an outlet conduit 2.

Mounted in a shoulder on the top inner edge of upperdiousing-ring B is acover rim 3 which carries cover I. The flat top of cover I supports theelectrode structures, the air blower means, the grain inlet means, andother elements including the 'high voltage transformer, all in .a

I manner that will fully appear below.

Brace plates 203 of the casing-supporting frame are positioned as shownin Figure 1, there being one on each side' of the apparatus (shown insection) and two in the back. These plates 203 divide the space betweenhousing-rings 3 and 3 into four arcuate openings through which ac-' cessmay be had to the interior of the machine. One of these arcuate openingsextends around the entire front (the bottom of Figure 6) of the machine.

Normally closing these arcuate openings, and overlapping housing-rings 3and 6, is a remov able band III which is tightened and thus held inplace by structure best shown in Figure 7. Band III is provided at itsends with flanges 231 and 209 and extending ugh a hole in flange 201, isacap screw 203, which is threadablyreceived in a hole in flange 203.When band I 3 is bein By providing means for and 48 and motor I3 aremounted as a unit, one

end being supported by an air supply conduit 43' and the other end beingsupported through an L conduit I7 by a casing-head I2 which iscentrally, positioned on casing cover I and is held in place by capscrews I3. Casing-head I2 has in tegral therewith a downwardly-extendinghollow dead shaft I4 upon which is mounted the stator of an electrodemotor 20 (see also Figure 2), the rotor of which is within and carriedby a motor casing 22 supported as later described. Extending downwardlyfrom casing 22 is a neck 23 2 and5) opening into an annular air exhaustmanifold I6. Manifold I8 communicates with ell conduit ll of exhaustblower I8 and thus completes an air exhaust circuit which is from hopperI, up through the center of hub 23, through neck 23, through dead shaftI4, through passageways I5, annular manifold I3, conduit I'I, and'blowerI8 to a suitable exhaust conduit.

Also attached to casing cover I by cap screws I3 7 is adownwardly-extending shell 38 which surrounds electrode motor 28 andcasing 22, but is spaced throughout so as to form a grain passagewaybetween its inner surface and the outer surfaces of casing 22, neck 23,and hub 25.

Electrode is depressed at its center to form a bowl-like portion 36 andshell 33 flares outwardly at its lower'end and cooperates with hub thetreatment zone.

bowl 38 across discharge sunface 31, and falls.

positioned, its ends are placed along the side of one of the braceplates 233, as shown at the right of Figure 1, so that when cap screw20' is turned to tighten band a, a substantially sealed casing is formedof cover "I. hopper, I, and band II. Band III may be removed byloosening cap screw 20 5 and then slipping itdown where it may be.

rested upon lugs 2 on posts I.

Cover 1 is provided with three sealed doors IIII (Figurefi) throughwhich access may be had to the upper portion of the interior of thehousing. It is also provided with windows (not shown) 4 through whichthe corona-like discharge and the operation of the machine within thehousing may be observed. Y

Mountedon the top .of casing cover I are two blowers, an air supplyblower l3, and an airexhaust blower I8, both driven by a high-speedmotor I9 mounted therebetween. Blowers I8 25 in directing the grainoutwardly through this bowl-like portion. The outer portion of electrode34 is provided with a radially extending dis-v charge surface 31 whichforms the lower wall of The grain thus passes from into hopper I. 1

Directly above rotatable electrode 34, so as to form the upper wall ofthe treatment zone, is a disc 39 of a vitreous dielectrical material,suchasglow power factor glass or quartz. Disc "is supported by upperhousing-ring l and is held against the lower surface of cover rim 3 by:disc-retaining ring 308. Disc-retaining ring; 308 is held in place by aplurality of headed pins 3I0 which extend inwardly through holes inupper housing-ring 3, and are limited in their inward movement by theirheads and held from outward movement by removable band I 3. Glued to theperiphery of disc 33, where it is'contacted by cover rim 3 anddisc-retaining ring 333, are two rings of vibration-damping material,such as felt.

QDirectIy above the discharge surface 31 and upon the upper surface ofdisc 33, is stationary electrode 42 which is of -a few mils thickness.'

In this embodiment, stationary electrode 42 is formed-by sand-blastingan annular portion of the uppersurface of disc 39, then covering the,

sand-blasted portion with a thin layer of lead and covering this with athin layer of aluminum,

the lead and the aluminum being applied by means ofa metal spray.Stationary electrode 32 is thus in intimate contact with disc 39 and isof suiiicient conductivity and dimensions to function as an electrode,but is thin enough to per- 'mit the rapid transfer of heat from disc 33to of insulator 45 are three studs 332 which co-' operate to carry upontheir lower ends an annular manifold 44. Each stud 332 is held in placeby an acorn nut 304 which is locked by a set screw- 306. Manifold 44 isprovided with an annular air passageway 3 which is shaped incross-section as shown, and is formedby channel member 3l2, a lowerinner ring member 3, and a lower outer ring member 316, which are heldtogether by suitable screws 3l8. The adjacent edges of lower ringmembers 3M and lid extend downwardly and are separated by an annular airslot 52.

Attached to the upper side of channel member M2 is a manifold coupling323 which is held in place'by screws 322 and which receives air from airsupply blower 48 and conduit td through a conduit it ,of dielectricmaterial. Channel member 3M is so shaped that passageway 3!! is enlargedat the point of its attachment to manifold coupling 323 so that airtielivered to manifold M escapes throughout slot iii in an evenlydistributed stream.

Manifold M is eii'ectively insulated from the grounded frame of themachine by members dill and M and at the same time air is deliveredthrough it to the upper surface of the upper electrode ti.

Manifold i t is provided at its inner and outer edges with enlarged rimsiii and 53, respectively, which extend beyond and thus shield stationaryelectrode 32 from physical and electrical damage. During operation,manifold i t is maintained at a high potential and the presence ofrounded rims ti and till lessens flux concentration on these edges andthus eliminates the danger of sparking. The spacing of rims hi and'iiilfrom disc is such that, in escaping, air passing from slot iii moves inintimate contact with electrode and disc it to effect cooling thereof.

in addition to its functions of distributing the air and shieldingstationary electrode d2, inanifold M also provides the high potentialelectrical connection with the stationary electrode till, and thus, ineifect, is a feeder. nection between manifold M and stationary electrode52 is formed by three leaf springs at which are equally spaced as shownin dotted lines in Figure 3, and which are riveted to lower inner ringmember 314 as shown in Figure 4. Leaf springs E l are so shaped thatthey are under tension when the elements are positioned as shown, andintimate contact is thus maintained between leaf springs 54 andstationary electrode 42.

The structure of the electrode motor 23 together with its mountingmeans, is best shown in Figure 2. Rigidly mounted upon the upper end ofdead shaft l4 and held in alignment by a stud 324 is upper frame 63; ina like manner, 9n th lower end of dead shaft I 4 is lower frame 3|.These two frames are held in place by a spanner nut 65 which is lockedin place on the lower end of dead shaft l4 by set screw 85. Frames 30and 3| provide a support for the electrode motor, casing 22, and theelements supported thereby. Casing 22 includes an upper casing cover'12, a center-cylindrical portion 13, a lower casing cover 13, and neck23. Casing covers 12 and 13 are held in place on the opposite ends ofcylindrical portion 15 by a suitable number of cap screws 14. Neck 23 isheld in place on the lower end of casing cover 13 by cap screws I3. Theupper end of easing cover 12 is provided with a downwardly extendingcenter flange II which extends into an annular recess 61 in frame 30,where it is supported by a ball bearing unit 13, mounted on this frame.In a like manner, lower casing cover 13 is provided with aflange M whichextends downwardly into recess 63 and is supported by a ball bearingunit 32. The juncture of casing cover l2 and framed!) is sealed by adust seal 83 of leather or other suitable material, and the juncture ofneck 33 and frame 3i is sealed with a similar dust seal M.

Rigidly held in place upon upper frame 33 by clamping ring 32 and asuitable number of cap screws "it, is stator-core til which carriesstatorwinding 3d. Surrounding stator-core t9 and rigidly clamped betweencasing covers it and iii, is rotor-core it which is provided with asuitable squirrelcage winding. In this embodiment, a three-phase motorhas been used and it has been provided with id poles so as to obtain arelatively slow speed at fill cycles. The conductors iti fromstator-winding t l extend inwardly through a recess (not shown),upwardly along dead shaft iii, through a hole it, and into a juncdil Theelectrical con i tion box tit. Within box tit, conductors E132 areattached to power supply conductors Eiti (Figure l) which extend fromthe source of power as will be explained below.

The means for removably attaching hub iii and rotatable electrode toneclt it is best shown in Figure t. Neclr is provided with a spider it),and depending from spider it is a screw threaded stud iii. in a likemanner, huh is provided with a spider iii' having a central collar itthrough which extends a sleeve-litre f nut 29. The lower end of nut iiiis flanged at it and carries four radial handles it?! for manualrotation. Surrounding the upper end of nut is a collar 3i which acts asa stop to prevent the movement of nut it downwardly through collarAttached to the inner surface of neck: and extending downwardly is akey'til, and attached "to hub ii is a tug ifey and lug til cooperate tolimit relative rotary movement icetween neclt it and hub Referring toFigure i, to install rotatable electrode ti t in position, band iii isloosened and rested upon lugs ill on posts The electrode, with its hubit and with nut it hanging in collar it, is slid in from the side (thebottom of Figure 6) on rails 3 (Figure 1) until hub 25 is directly belowneck 23, and nut 29 is directly below stud 2i. Nut 29 is then raised bymeans of handles 32 until it engages stud 21 and is rotated whileelectrode 34 is manually held at its Y periphery so that it cannotrotate. As nut 23 rotates and progresses upwardlyon stud 2!, the flangedportion 29' engages the lower surface of collar 30 and lifts electrode34.

During this engagement of nut 29 with stud 21, stud 2'! may tend torotate due to the fact that it is rotatably supported through spider 23through which the grain passes.

25 upwardly until the upper end of hub 25 telescopically' engages thelower end of neck 23; nut 23 is then tightened and electrode 34 issecurely supported so that it will be rotated by motor 20.

Referring again to Figure 1, mounted in the bottom of hopper I isagrating for the purpose of, permitting the grain to flow from thehopper, and for preventing, nevertheless, the passage of foreignmaterial, such as pieces of disc 39 if it should break. This gratingconsists of a series of posts 51 supporting superimposed louvers 53These posts supp rt a cap 59 which directs the grain through thelouvers.

Extending between vertical posts 4 are two cross-frame members 220 whichprovide mount ing means for a high-frequency, low-voltage alternator 55at the right, and control apparatus 35 at the left. Control apparatus 85includes a control switch 332 which operates switching means to controlalternator 55and the connection of its output, a control switch 334which operates switching means to start and stop the electrode motor andblower motor is which are connected in parallel, analternator fieldcontrol rheostat 336, and a wattmeter 338;

Mounted on the top of easing cover 'I is a highelectrode motor 20 andblower motor i9 operate in parallel and are connected to the: switchingmeans controlled by the control switch 334 through conductors 362. Oneside of the current coil of wattmeter 338 is connected to conductor 92and the other side is connected to conductor 90; one side of itspotential coil is connected to conductor 92, and the other side isconnected through potentiallead 354 to conductor 94. One side of theoutput of alternator 55 is connnected directly by conductor 94 to thelow side of the winding of auto-transformer 56, and this conductor isconnected directly at 38 to the grounded frame of the machine. The

other sideof the output voltage of alternator is connected throughswitching means (not shown) and conductors 30 and 92 and thence throughlow-voltage insulator 342 to the tap 96 of the auto-transformer winding.The high side I" of the auto-transformer is connected by a conductor 344through a high-voltage insulator 343'to manifold 44.

Rotatable electrode 34 is' effectively grounded voltage output ofauto-transformer 55 is connected directly across the electrodes. Thispotential is of such a value that suitable discharges, preferably ofdisruptive corona-like form, occur in thetr'eatment zone, which isbetween the lower surface of disc 39 and discharge surface 31 of therotatable electrode "34.- At the same time. rims 5| and 53 on manifold44 and the where it contacts casing 22 and is given a swirling I motionand is conveyed to the upper surface of the rotatable electrode 34. Itthen passes outwardly through the treatment zone to hopper I from whichit passes by an outlet conduit 2.- During the movement of the grainthrough the treatment zone, it follows turbulent curvilinear paths sothat it is eflectively treated and any insect life which is entrainedwith the grain is sought out by the discharges and destroyed.

vDuring movement of the grain through the treatment zone, air isdelivered by blower 48 through conduits 43' and 41 and conduitconnection 320 to manifold- 44. In passing from manifold 44 through slot52, the air impinges downwardly upon the surface of stationaryelectrodev 42 and divides, one stream moving beneath each of rims iiiand 53. These two streams then combine and flow outwardly frombetweenthe irmer edge of disc 33 and the lower end of shell '38. At this point,the air is thoroughly mixed with the grain moving outwardly through thetreatment zone, and, thus, as the grain passes through the treatmentzone, it is accompanied by an additional quantity of air which i madesuflicient to bring-the dust concentration in the air below thatnecessary to form an explosive mixture. In movement past electrode 42and through the treatment zone, the air is given sufflcient turbulenteflect to cause it to carry away the heat incident to the treatmentprocess, in-

cluding the heat caused by dielectric losses in disc obtaining a highpotential gradient within the treatment zone at all.times.

After leaving the treatment zone, the air passes downwardly and iswithdrawn from the machine by exhaust blower l3, through the center' ofhub 25, neck 23, dead shaft l4, passageways 15, manifold I5, and Lconduit l1. Ex-

haust blower i8 delivers substantially more air through its supportingmeans to the frame of the machine and thus, the high frequency,highdownwardly turned periphery of rotatable electrode 34 effectivelyprevent undesirable concentration of flux which might result insparking.

than does air supply blower 48, with the result that a partial-vacuum orsubatmospheric pressure'condition is maintained in the lower part ofthehousing and air is continually being drawn upwardly. through 'grainoutlet conduit 2. This air-washes the grain andeffectively removes anyair-ionization products might might otherwise betrapped and carrieddownwardly with the grain. At the same time, it has been found that.dust forming part of or accompanying the materials being treated is notremoved by blower it, but remains with the materials.

' This partial-vacuum condition also tends to draw air into the housing.through any leaks that might be present. Thus, the air-ionizationprodfeet of air per minute from blower." and by exhausting 600 cubicfeet of air per minute from blower l8.

. While the length of discharge gap, which is, in efiect, the thicknessof the treatment zone, varies with the materials being treated, thevoltage, frequency, etc., it has been found that a gap of inch to inchwith a disc 39 of 1%; inch thickness, and with a corresponding voltagewhich ranges from 20,000 volts to 30,000 volts, gives satisfactoryresults. A gap of inch has been used with semolina and a gap of inch hasbeen used with corn; other lengths of gap have been used with othermaterials. The length of gap may be varied by changing the length ofvhub 25. A high-frequency of 500 cycles per second has been used withexcellent results but lower and higher frequencies may be used. Afrequency of 60 cycles has been found satisfactory except that thequantity of material being treated is less; frequencies substantiallyhigher than 500 cycles tend to result in higher dielectric losses andthus excessive heating of disc til.

When a material. such as spring wheat is being treated, and with a iiowoi 10 bushels per minute, the watt input is on the order of M00. With arise in moisture content, this Wattage increases and with lower moisturecontent this wattage is correspondingly less.

Thus it is seen that the above-mentioned obiects are obtained and that ahighly eihcient and As many possible embodiments may be made of themechanical features oi the above invention and as the art hereindescribed might be varied in various parts, all without departing fromthe scope of the invention, it to be understood that all matterhereinabove set forth, orshovm inthe accompanying drawings is to beinterpreted as illustrative and not in a limiting sense.

I claim:

1. in electrical apparatus in which a product is subjected to anelectrical discharge, thecom bination of, a pair of electrodes, adielectric plate between said electrodes and spaced from one of saidelectrodes so as to form a treatment zone, an air manifold having a jetadjacent one of said electrodes, means to deliver air from saidinaniiold through said jet into heat-conducting relationship with saiddielectric plate and through said treatment zone.

2. In an electrical apparatus in which a product is treated in atreatment zone by subjecting it to the electrical discharge resultingfrom impressing a high potential across a pair-of electrodes, thecombination of, a rotatable plate having anelectrode discharge area, amotorior rotating said plate, means to conduct the. product who treatedto said plate around said motor, and means to conduct air through saidmotor in a direction opposite to that of the travel of the productaround the motor.

3. In an electrical apparatus in which a product is treated in atreatment zone by subjecting it tothe electrical discharge resultingfrom impressing a high potential across a pair of electrodes, thecombination of, a rotatable plate having an electrode discharge area, amotor for rotating said plate, means to conduct the product to betreated to said plate around said motor, means to conduct air throughsaid motor in a direction opposite to that of the travel of the productaround the motor, and an electrode to cooperate with said electrodedischarge area.

4. In an electrical apparatus in which a product is treated in atreatment zone by subjecting it to the electrical discharge resultingfrom impressing a high potential across a pair of electrodes, thecombination of, a rotatable plate having an electrode discharge area, amotor for rotating said plate, means to conduct the product tobe-treated to said plate around said motor, means to conduct air throughsaid motor in a direction oppotill iii

carried by said frame structure and its rotor rigidly carried by saidcasing, a shell enclosing said casing and forming an annular passagewaybetween its inner wall and the outer wall of said casing, an electrodestructure having a central opening in alignment with the openingthrough,

said dead shaft and having an annular discharge surface, and meansrigidly attaching said electrode structure to the lower end of saidcasing.

ii. In electricalv treatin apparatus, the com-- bination of, a plate ofdielectric material, an electrode structure having an annular dischargesurface spaced from one side of said plate form an annular treatmentzone therelcetween, ascope ating electrode positioned upon the otherside or" said plate in intimate contact therewith, said plate beingroughened along its surface where it is contacted by cooperatingelectrode and said cooperating electrode being formed by a thin layer oilead covered by a thin layer or aluminum.

i. In electrical treating apparatus, the combination of, a plate ofdielectric material, a first electrode structure positioned upon oneside of said plate, and a second electrode structure positioned upon theother s' e oi plate and spaced therefrom to a material directing andconfining passageway comprising an annular treatment zone one Wall ofwhich is formed by the surface of said second electrode structure andthe other wall of which is formed by the surface of said plate.

8. In electrical treating apparatus of the type wherein a dry'materialbeing treated is subjected to electrical discharges, the combination of,a settling chamber to receive the treated material, a material dischargeconnected to the bottom of said settling chamber through an openingwhich may be substantially sealed by the treated material, a gasdischarge connected to the top of said settling chamber to remove gasfrom said settling chamber substantially free of particles of thetreated material and to draw gas in through said material discharge,whereby the material is treated and the fine particles are permitted tosettle and the gas accompanying the material during treatment is removedand discharged through the gas discharge,

9. In electrical treating apparatus, the combination of: treatingapparatus including means defining an annular treatment zone, anannularrotatable member to move the material through the treatment zone, and amotor concentrically mounted with respect to said treatmentzone v andconnected to rotate said rotatable member;

10. In electrical treating apparatus, the combination of: treatingapparatus including means defining an annular treatment zone, an annularrotatable member to move the material through the treatment zone, and amotor concentrically mounted with respect to said treatment zone andconnected to 'rotate said rotatable member; a settling chamber toreceive the treated material from the treatment zone and providing meansto effectively stop the movement of the treated material and theaccompanying gas with the result that the material collects at thebottom of the settling chamber; a first passageway connected to thebottom of said settling chamber to permit theremoval of treatedmaterial; a second passageway opening through said motor to the centerof the top of said settling chamber to permit the removal of gasdischarged from the treatment zone; and means to withdraw gas from saidsettling chamber through said second passageway in sumcient quantitytocause gas to flow into said first passageway and thereby wash thetreated material as it is being discharged.

11."In electrical treating apparatus of the type end of said passagewayextending along said dead shaft.

13. In electrical treating apparatus, the combination of, a plate ofdielectric material, an electrode structure having an annular dischargesurface spaced from one' side of said plate to face spaced from one sideof said plate to form wherein a dry material being treated is subjectedto electrical discharges, the combination of: a

settling chamber to receive the treated material and having a bottomwall the shape of an inverted conewith a material discharge opening atits lowest point; a louver means mounted at the bottom of said settlingchamber and surrounding said material discharge opening comprising, aplurality of annular louvers mounted one above the other in'spacedrelationship to provide annular vpassageways therebetween throughwhich the treated material may move radially into the center of saidlouver means and to said material discharge opening.

12. .In treating apparatus, the combination of:

a supporting structure; a dead shaft depending from said supportingstructure and having an opening therethrough; a frame structure surashell construction enclosing said frame structure and the adjacentportion of said dead shaft rounding and rigidly carried by said deadshaft;

ing along said dead shaft; and an electrode structure having a centralopening in alignment with the opening through said dead shaft and havingan annular discharge surface -open to the lower electrode structurehaving an annular discharge surface spaced from one side of said plateto.

form an annular treatment zone therebetween; la cooperating electrodepositioned upon the other side of said plate in intimate contacttherewith comprising a thin metallic sheet; an elongated metallic jetmeans positioned adjacent said co-' operating electrode to direct astream of gas thereon, said metallic jet means forming a rigidelectrical conductor; and a plurality of spring pressed contactorscarried by said metallic jet means and resiliently held against saidcooperating electrode to provide an electrical connection therewith.

16. In electrical treating apparatus of the type wherein a product istreated by subjecting it to discharges resulting from producing a highpotential gradient within the treatment zone, the combination of: adielectric plate having a central opening therein; a rotatable structuremounted concentrically with respect to said central opening andincluding a concentrically mounted annular electrode positioned beneathsaid plate and spaced therefrom to define an annular treatment zonebetween the upper surface of said electrode and the adjacent lowersurface of said plate; and means to deliver material to be treated tothe central portion of said rotat able structure'through said centralopening and. to deliver an excess quantity of gas to the treat ment zonewith the-material to be treated.

I 1'7. In electrical treating apparatus of the type wherein a product istreated by subjecting it to discharges resulting from producing a highpotential gradient within the treatment zone, the combination of: adielectric plate having a cen-. tral opening therein; a rotatablestructure mounted concentrically with respect to said central openingand including a concentrically -mounted annular electrode positionedbeneath dished portion of said rota able structure-through said centralopening and to deliver an exce quantity of gas to the treatment zonewith the material to be treated;

18. In the art of treating dry bulk materials where the materials aresubjected to discharges resulting from producing a high potentialgradient, the steps of, producing a high potential gradient within atreatment zone to thereby cause corona-like discharges, passing thematerial through the treatment zone and into a settling chamber topermit the material to settle and assume its normal condition,withdrawing the treated material from the bottom of the settlingchamber, and withdrawing gas from the top of the settling chamber insufficient quantity to cause a eounterflow of gas through the treatedmaterial being withdrawn but without disturbing the settling process.

19. In the art of treating dry bulk materials where the materials aresubjected to discharges resulting from producing a high potentialgradient, the steps of producing a high potential gradient within atreatment zone to thereby cause corona-like discharges, passing thematerial being treated together, with an excess of gas through thetreatment zone and into a settling chamber, removing excess gas from thetop of the settling chamber substantially free of the material beingtreated, and removing the treated material from the bottom of thesettling chamber.

' FRANKLIN S. SMITH.

